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• W2171921639 abstract "Redox thermodynamic properties and catalytic activities of metal oxides were studied to gain insight into the fundamental relationships between those properties. Catalysts based on iron oxides, vanadium oxides, and molybdenum oxides were studied because of their industrial importance to the water-gas-shift and partialoxidation reactions. Redox properties of 5wt% and 15wt% V2O5/Al2O3 catalysts calcined at 753 K and 973 K were measured using coulometric titration at 748 K. 5wt% V2O5/Al2O3 was found to be thermally stable and its reduction from V+5 to V+4 occurred at P(O2) values between 10-4 and 10-19 atm and from V+4 to V+3 at a PO2 of 10-28 atm. The redox isotherm for a 15 wt % V2O5/Al2O3 calcined at 753 K showed a sharper reduction from V+5 to V+4 at P(O2) of 10-20 atm. Upon calcination at 973 K, the 15 wt % sample underwent a solid state reaction resulting in AlVOx species that reduce in single step from V+5 to V+4 from at P(O2) of 10-6 atm. All of the V2O5/Al2O3 catalysts had similar activities for the selective oxidation of CH3OH to CH2O, suggesting that oxygen removal from the surface is not the rate limiting step for this reaction. For C3H8 oxidative dehydrogenation, the 15 wt % V2O5/Al2O3 sample that was calcined at 973 K was active only for the complete oxidation of propane to CO2 and H2O, while all other catalysts were similarly active and selective to C3H6. The results show that redox thermodynamic influences on reaction rates and selectivities can vary from null to significant and depend on exact mechanism of reaction of interest. Redox isotherms at 973 K for supported iron oxide were examined as a function of iron loading on zirconia. Zirconia supported iron had a redox isotherm that showed a well-defined steps corresponding to transitions of Fe2O3 → Fe3O4, Fe3O4→FeO and FeO→Fe, with the transition of Fe2O3→Fe3O4 shifting to significantly higher pressures of oxygen compared to bulk iron, which makes surface iron easier to reduce and harder to oxidize compared to bulk iron oxide. Water gas shift reaction rates over supported iron catalysts and bulk iron showed that specific rates for supported samples were orders of magnitude slower than bulk iron due to thermodynamically higher energy barrier of catalyst reoxidation in supported catalysts. A study of Mo-based mixed oxides showed that the thermodynamic redox properties of Al2(MoO4)3, Zr(MoO4)2, Cr2(MoO4)3, and MgMoO4 at 873 K are nearly identical to each other but differ significantly from that of SrMoO4. None of the mixed oxides exhibit thermodynamic properties similar to that of bulk MoO3. The similarities and differences between these mixed oxides likely result from the presence of isolated (MoO4)2tetrahedra in the oxidized forms and two different types of Mo-O-Mo bonding in the reduced forms. However, the catalytic activities for methanol oxidation were much lower than that of bulk MoO3. It appears that the low activity for the bulk mixed oxides is the result of the Mo+6 cations within the (MoO4)2anions being inaccessible to reactants. Degree Type Dissertation Degree Name Doctor of Philosophy (PhD) This dissertation is available at ScholarlyCommons: http://repository.upenn.edu/edissertations/355 Graduate Group Chemical and Biomolecular Engineering First Advisor Raymond J Gorte Second Advisor John M Vohs" @default.
• W2171921639 created "2016-06-24" @default.
• W2171921639 creator A5000126015 @default.
• W2171921639 date "2011-01-01" @default.
• W2171921639 modified "2023-09-26" @default.
• W2171921639 title "A study of red./ox. thermodynamic and catalytic properties of metal oxide materials" @default.
• W2171921639 cites W1488831428 @default.
• W2171921639 cites W1495428074 @default.
• W2171921639 cites W1561570274 @default.
• W2171921639 cites W1579267068 @default.
• W2171921639 cites W1606216290 @default.
• W2171921639 cites W1619164995 @default.
• W2171921639 cites W1622577498 @default.
• W2171921639 cites W1646339107 @default.
• W2171921639 cites W1916513634 @default.
• W2171921639 cites W1964831190 @default.
• W2171921639 cites W1968637567 @default.
• W2171921639 cites W1969008696 @default.
• W2171921639 cites W1969207185 @default.
• W2171921639 cites W1970394793 @default.
• W2171921639 cites W1972656312 @default.
• W2171921639 cites W1972991191 @default.
• W2171921639 cites W1977949438 @default.
• W2171921639 cites W1978475523 @default.
• W2171921639 cites W1978878636 @default.
• W2171921639 cites W1980095248 @default.
• W2171921639 cites W1981142591 @default.
• W2171921639 cites W1982510557 @default.
• W2171921639 cites W1983053022 @default.
• W2171921639 cites W1983977046 @default.
• W2171921639 cites W1984845688 @default.
• W2171921639 cites W1986120616 @default.
• W2171921639 cites W1988745176 @default.
• W2171921639 cites W1989224620 @default.
• W2171921639 cites W1991965705 @default.
• W2171921639 cites W1993102531 @default.
• W2171921639 cites W1995677756 @default.
• W2171921639 cites W1996490256 @default.
• W2171921639 cites W1997223842 @default.
• W2171921639 cites W1998425991 @default.
• W2171921639 cites W1998448506 @default.
• W2171921639 cites W1999034211 @default.
• W2171921639 cites W1999345050 @default.
• W2171921639 cites W2003579240 @default.
• W2171921639 cites W2006539540 @default.
• W2171921639 cites W2007144623 @default.
• W2171921639 cites W2008080867 @default.
• W2171921639 cites W2010178277 @default.
• W2171921639 cites W2011487266 @default.
• W2171921639 cites W2013303305 @default.
• W2171921639 cites W2014147249 @default.
• W2171921639 cites W2014843822 @default.
• W2171921639 cites W2015856769 @default.
• W2171921639 cites W2017581789 @default.
• W2171921639 cites W2017827699 @default.
• W2171921639 cites W2019901122 @default.
• W2171921639 cites W2026760723 @default.
• W2171921639 cites W2028192467 @default.
• W2171921639 cites W2029536589 @default.
• W2171921639 cites W2029967155 @default.
• W2171921639 cites W2032566559 @default.
• W2171921639 cites W2033638138 @default.
• W2171921639 cites W2034500026 @default.
• W2171921639 cites W2037733047 @default.
• W2171921639 cites W2040816833 @default.
• W2171921639 cites W2043799417 @default.
• W2171921639 cites W2044684556 @default.
• W2171921639 cites W2045179624 @default.
• W2171921639 cites W2048126525 @default.
• W2171921639 cites W2049346793 @default.
• W2171921639 cites W2050484989 @default.
• W2171921639 cites W2051248161 @default.
• W2171921639 cites W2051872807 @default.
• W2171921639 cites W2053244785 @default.
• W2171921639 cites W2057376504 @default.
• W2171921639 cites W2057834496 @default.
• W2171921639 cites W2059200132 @default.
• W2171921639 cites W2063813127 @default.
• W2171921639 cites W2067250408 @default.
• W2171921639 cites W2068282828 @default.
• W2171921639 cites W2071010868 @default.
• W2171921639 cites W2078529882 @default.
• W2171921639 cites W2079492959 @default.
• W2171921639 cites W2081735902 @default.
• W2171921639 cites W2083737222 @default.
• W2171921639 cites W2083943817 @default.
• W2171921639 cites W2086909663 @default.
• W2171921639 cites W2087498102 @default.
• W2171921639 cites W2089085969 @default.
• W2171921639 cites W2092878519 @default.
• W2171921639 cites W2094565162 @default.
• W2171921639 cites W2096378183 @default.
• W2171921639 cites W2099728949 @default.
• W2171921639 cites W21027212 @default.
• W2171921639 cites W2108575423 @default.
• W2171921639 cites W2132905138 @default.
• W2171921639 cites W2133865326 @default.
• W2171921639 cites W2139705150 @default.
• W2171921639 cites W2139715371 @default.
• W2171921639 cites W2155276367 @default.

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